Ques. 3. What are the criteria used in the classification of Algae? Give outline of Fritsch’s classification of Algae.
Write note on classification of Algae.
Give an outline of classification as proposed by F. E. Fritsch.
Point out the main characters which distinguish the important algal groups from one another.
Distinguishing Characters of Important Algal Groups
The main criteria on the basis of which different groups of algal may be differentiated from one another are:
(a) Nature of the food reserve. .
(b) Chemical and physical nature of cell wall.
(c) Number, Morphology and Orientation of flagella.
(d) Modes of reproduction and nature of gametes.
(e) Type of photosynthetic pigments and photosynthetic apparatus.
(f) Cellular organization.
(g) Thallus organization.
(h) Habitat
Some of the distinguishing features of important algal groups are as follows:
(A) Class-Myxophyceae or Cyanophyceae
(1) Pigments are not localized in definite chromatophores. They are localized in the peripheral portion of the protoplast.
(2) The plants are blue green in colour due to the presence of pigment. C. phycocyanin, along with chlorophyll, a, beta Carotene and Xanthophylls.
(3) The reserve food products are proteinaeous and cynophycean starch.
(4) Nucleus absent, Named DNA fibrils (not associated with histones) are present.
(5) Flagella absent.
(6) Sexual reproduction is absent.
(7) Cell wall is mucopolymeric.
(8) Majority of them are fresh water, a few may be marine.
(9) Thylakoids occurs singly.
(10) Pyrenoids absent.
(11) Procaryotic.
(B) Class-Chlorophyceae
(1) Pigments are localized in definite chromatophores.
(2) Chromatophores are with 2 to 6 thylakoid grouped in a bond.
(3) Pyrenoids present with sheath.
(4) The photosynthetic food products are starch.
(5) Pigments are like higher plants i.e., chlorophyll ‘a’ chlorophyll ‘b’ ß carotenes and Xanthophylls.
(6) Nucleus is distinct, have nucleolus, spindle and centrometric chromosomes made up of any protein and DNA fibrils associated with histones.
(7) Flagellae are 2, 4 or more, all are equal i.e., isokontae type anterior acronematic.
(8) Cell wall is of cellulose.
(9) Sexual and asexual reproduction are of distinct types.
(10) Majority of them are fresh water, few are marine.
(11) Eucaryotic.
(C) Class-Bacillariophyceae (diatoms)
(1) Pigments are localized in chromatophores.
(2) The chromatophores are golden brown or yellow in colour due the presence of diatom in pigment along with chlorophyll a, Beta Carotene and Xanthophylls.
(3) Reserve food products are fats or Volutins.
(4) Chromatophores with 3 thylakoid bands.
(5) Pyrenoids naked.
(6) Nucleus distinct with nucleolus, spindle and centrometric and chromosome made up of protein and DNA fibrils associated with histones.
(7) The silicified nature of cell wall which consists of two highly perforated overlapping pieces sometimes bearing structures like spines and bristles,
(8) One or two anterior flagella may be found.
(9) Sexual reproduction is present, with auxospore formation.
(10) Usually unicellular, sometimes colonial.
(11) Usually diplontic.
(12) Found in fresh water and sea water.
(13) Eucaryotic.
(D) Class-Phaeophyceae
(1) Pigments are localized in definite chromatophores.
(2) They are brown in colour due to presence of Fucoxanthin along with chlorophyll and Beta Carotene.
(3) Chromatophores with 4 thylakoid bands.
(4) Pyrenoids are projecting and naked.
(5) Eucaryotic.
(6) Nucelus is distinct, and chromosome made up of proteins and DNA fibrils associated with histones.
(7) Flagella usually two, lateral in position, usually unequal, one acronematic and one pentonematic.
(8) Cell wall of cellulose with alginic and fucinic acids.
(9) Reserve food is chrysolaminarin, leucosion and manitol.
(10) Sexual reproduction quite distinct.
(11) Alternation of diploid asexual generation with haploid sexual generation.
(12) Mostly marine, rarely fresh water.
(E) Class-Rhodophyceae
(1) Pigments are localized in definite chromatophores.
(2) They are red in colour due to the presence of r-Phycoerythrin along with chlorophyll a, ß carotene c-Phycocynin and Xanthophylls.
(3) Chromatophores are with single and widely separated thylakoids.
(4) Pyrenoids naked.
(5) Nucleus distinct with nucleolus, spindle and centrometric chromosomes made up of protein and DNA fibrils associated with histones.
(6) Flagella are entirely absent.
(7) Cell wall is non-cellulosic polysaccharides or with xylan, polyxylan, galactose and xylose.
(8) Reserve food material is floridian starch, galactan sulphate.
(9) Sexual reproduction is most advanced and is of special type.
(10) Mostly marine rarely fresh water.
(11) Eucaryotic.
BSc 1st Year Botany Classification of Algae Sample Model Practice Question Answer Papers
BSc 1st Year Botany Classification of Algae Sample Model Practice Question Answer Papers
BSc 1st Year Sample Model Practice Mock Test Question Answer Papers
BSc 1st Year Botany Classification of Algae Sample Model Practice Question Answer Papers